Download File

 The endocrine system is made up of the cells,
tissues, and organs that secrete hormones into
body fluids such as the blood stream.
 Hormones diffuse into the bloodstream, and
eventually act on cells called target cells.
 Glandular cells of the endocrine system release
hormones into the bloodstream, which carries these
messenger molecules everywhere.
 The endocrine system is precise because only target
cells can respond to a hormone. Target cells have
specific receptors that other cells do not have.
The endocrine system helps regulate metabolic
processes by:
 Controlling the rates of certain chemical reactions
 Aid in the transport of substances across membranes
 Help regulate water and electrolyte balances
 Playing a vital role in reproduction, development, and
growth
 Pituitary gland
 Thyroid gland
 Parathyroid gland
 Adrenal gland
 Pancreas
 Pineal gland
 Reproductive glands
 Kidneys
 Thymus
 Located at the base of the brain, where a pituitary stalk
attaches it to the hypothalamus.
 Stimulates cells to increase in size and divide more
frequently
 Pituitary dwarfism insufficient secretion of growth
hormone; body parts normally proportioned, mental
development is normal
 Gigantism oversecretion during childhood; usually a
result of a tumor which can cause oversecretion of
other pituitary hormones; often has several metabolic
disturbances
 Acromegaly oversecretion during adulthood;
enlarged heart, bones, thyroid gland, facial features,
etc
 Milk production in lactating women
 Controls thyroid gland secretions
 Controls the hormones of the adrenal gland
 Exert their actions on the gonads
 Decreases urine formation.
 Regulates the water concentration of body fluids.
Diabetes insipidus (too little ADH) person may produce as
much as 25-30 liters of very dilute urine per day, and solute
concentrations in body fluids rise.
Oxytocin (OT)
 Causes contraction of the uterine walls during childbirth
 Contracts specialized cells associated with the milk-
producing glands and their ducts.
 May be given to ‘induce’ labor (Pitocin) and/or following
childbirth to minimize risk of hemorrhage
 Located below the larynx, anterior to the trachea
 Consists of two broad lobes connected by an isthmus
 Made of many secretory parts called follicles.
 Regulate metabolism of carbohydrates, proteins, and
lipids
 Basal metabolic rate how many calories the body
must consume at rest in order to maintain life
 Required for normal growth and development
 Essential to nervous system maturation
 Lowers blood calcium and
phosphate ion
concentration
 Inhibits release of calcium
and phosphate ions from
the bones
 Increases excretion of
calcium and phosphate
ions by kidneys
 Common among older adults
 Fatigue and weight gain

 Elevated metabolic rate, restlessness, and overeating
 Eyes protrude because of swelling behind them
 Produces a bulge in the neck because the thyroid
gland enlarges
 Endocrine (secretes hormones) and exocrine
(digestive juices) gland
 Located posterior the stomach




 Hormones of the Pancreatic Islets
 Glucagon
 Stimulates the liver to break down glycogen and
convert certain noncarbohydrates, such as amino
acids, into glucose
 Raises blood sugar concentration
 Insulin
 Stimulates the liver to form glycofen from glucose and
inhibits conversion of noncarbohydrates
 Decreases blood glucose (sugar) concentration
 Pineal Gland
 Located deep between the cerebral hemispheres, attached to the
thalamus
 Produces Melatonin:
 Produced in response to light conditions received by the retinas of the
eyes.
 Involved in regulation of circadian rhythms of the body
 Thymus
 Located posterior to the sternum between the lungs
 Thymosin- important in immunity

 Reproductive Glands
 Testes  produces testosterone
 Ovaries  produces estrogen & progesterone
 Placenta produces estrogen, progesterone & gonadotropin
 11.11 Stress and Health
 Physical factors include extreme heat or cold, decreased oxygen,
infections, injuries, prolonged heavy exercise, and loud noises.

 Psychological factors include thoughts about real or imagined dangers,






personal losses, and unpleasant social interactions or feelings of anger,
fear, grief, anxiety, depression, and guilt.
Responses to Stress
USE FIGURE 11.18
Hypothalamus
helps prepare the body for “fight or flight” by triggering sympathetic
impulses to various organs
stimulates epinephrine release, intensifying the sympathetic responses
secretes corticotropin-releasing hormones, which sets into motion
more lasting responses to stress